Defunct brands-

Telefunken.  I owned their M242 Reel to Reel and Acusta Hi Fi T250 and V250 Tuner and Amplifier, and Telefunken speakers.  Amazing sound, 4 ohms, 35 wpc. Only 250 Acusta series systems were made, they were a special commemorative run.  I still have the amp, 1 channel is bad. A guy in Europe is rebuilding them, selling them for $6000 US. Actually a good deal.

Verity Audio speakers. I own the Parsifal Encores. Love 'em.

I own a MFA Magus Pre amp. Though not in business anymore,

Scott Frankland still offers upgrades for it. 

He did some upgrades for me a few years back 

Yes, I have several pieces of B&K equipment, amplifiers and pre-amplifiers. I still love the sound. I used to own some Dahlquist DQ-20 speakers, they were ok. Sadly the company died with Jon Dahlquist. The main designer went on to found Nola Speakers as I recall. 

Cambridge Soundworks who actually had stores in malls to sell their equipment.  Bought equipment about 30 years ago.  I had a 5.2 system and a 7.2 system with a pair of 4 way towers with 300 watt amps in each to power the woofers.  After they went out of business one of the amps went and after several attempts at repairing it I sold the towers and center channel.  I still use 4 of the surrounds and I’ve replaced the 5.2 system with a Sonos system.